Fixed wing aircraft are judged to be low flying when they are less than 2000 feet from the ground. Light propeller driven aircraft and helicopters are judged to be low flying below 500 feet from the ground during the day and below 2000 feet at night. To manage low flying traffic density and increase flight safety, an authority divides the UK into defined Low Flying Areas (LFAs). The operating heights and areas used prevent reliable radar or radio coverage or provision of Air Traffic services. Users can book area entry/exit times and locations via a centralised booking cell, or in some cases a controlling authority. Booking requirements are designed to manage traffic density and provide an audit trail, for example in the case of low flying complaints or incidents. During the day, users are invariably unaware of any other booked users' detailed routes or timings. At night, users should be aware of others' intended general routing and outside timings, such as, for example, approximate times for entry into and exit from a certain area.
There are a number of bases from which low flying activity may be coordinated. Flight activity planned by a base may be publicised by the base to one or more other bases. Typically a base may provide details of flight plans to other bases chosen by that base. A base may even choose not to share details of flight plans with other bases. An attempt is also made in the base to analyse any potential areas and/or times of conflicts with plans from the same base or flight activity information received from other bases. A conflict may be, for example, where plans and other information indicate that two aircraft may come to within a short distance from each other.
Plans made available by various bases vary in their format, level of detail and provision method. For example, some bases may provide more detail on their planned activity than other bases. Some bases may provide information on their planned activity in an electronic format, and others may provide information in another format, such as sketches, faxes, or using the telephone. As a result, it is difficult for a base to identify conflicts between plans of that base and plans of other bases.
If a conflict with a plan from another base is identified, a base typically changes its plan, but does not provide information on the changes. Therefore, other bases may be unaware of the new plan. Furthermore, late changes to a flight plan may result in new conflicts, and it may take considerable time to review flight plan changes and identify the new conflicts.
The lack of information exchanged between bases, and the potential for errors when determining conflicts, may increase the risk of air-to-air collisions or proximity incidents.